Toilet Hard Flush Replace Worn Gasket On Mansfield Flush Valve

If the toilet becomes hard to flush at the handle, and has a sticking at the plunger bottom, it may mean the flush valve seal gasket needs to be replaced.

The rubber seal deteriorates, changes shape to conform with the float that sucks or sticks to each other making the handle hard to flush. So replace the rubber gasket on the flush valve.

First, look at these possible issues:

  1. Check the Chain to see if the chain is snagging to something.
  2. Check Chain length so when flushed, the flapper seal should rise and close again properly.
  3. Check the Flapper isn’t worn out as they will stick or leak.
  4. Check the Handle for binding, cracks and the nuts that hold the handle in place.

The flush valve rubber seal changes shape through deterioration to conform to the shape of the float and creates “vacuum” type feeling that sucks or sticks to each other making the handle hard to flush.

The flush valve is the device that controls how much water flows from the tank into the toilet bowl. Sometimes it looks like a flapper with a chain pulling up and down. A Mansfield toilet has a tower flush valve that lifts up and down. The seal on the flush valve is a rubber ring, and deteriorates, then sticks to the tower, stopping the handle from lifting the flush valve.

The flush valve gasket seals are common at hardware stores, though know or bring the old one.
Kohler gaskets 2 Pack, cost $7, yellow in color, and 2 red gaskets for Mansfield or American Standard are $6.

The plunger/float flush valve sits on the rubber ring. You want to make sure it goes back the same way. All you have to do is unscrew the center piece on the flush valve and loosen the flush lever and the center piece and the flush valve will pull off exposing the valve seal to be replaced.

Clean the bottom of the flush valve itself when you replace the seal, raise the flapper and clean it off.

Mansfield toilets come with a water saver flush valve, so a special handle fits through a loop to lift the seal.

Mansfield toilet flush valve seal replacement directions:
Turn off water.

  1. Disconnect the handle.
  2. Flush valve open so the water empties out.
  3. Disconnect water refill tube from top of the flush valve, tower assembly, remove gently.
  4. Unscrew the cap on top that the refill tube went into. It looks like a little flat donut on flush valve tower.
  5. The whole valve tower will slide up and off, with the red gasket on the bottom.
  6. Remove the old red rubber ring flush valve seal, it stretches.
  7. Slide the new gasket into place in the groove. When fitted properly, you can rotate the ring in the groove.
  8. Reassemble – slide the tower back on, screw on flat cap, connect the handle, and turn on the water.
    Turn on the water.

The threads on the nut inside the tank are left-handed. They turn the opposite direction than most threaded fittings.

The worst ones are the solid flappers with a gasket on the bottom found on Kohler toilets and others.